Plasmonic Nanoantenna Array-Based Sensor for Air Parameters Monitoring Purpose

Plasmonic nanoantennas have earned significant acclaim for their remarkable ability to couple light from free space into sub-wavelength-sized structures and to enhance the confinement of the electric field. One of the most promising applications of plasmonics is refractive index sensing. To study the optical properties and near-field calculations of the nanoantenna, three-dimensional finite-difference time-domain (FDTD) simulations were conducted using commercially available Maxwell equation solvers, such as Lumerical software. A significant enhancement in electric field intensity and maximum absorption cross-section were observed when an array of plasmonic nanoantennas was used compared to a plasmonic nanoantenna dimer. The proposed device is used to sense changes in major air parameters such as carbon dioxide (CO₂) gas concentration and atmospheric pressure. Sensitivities as high as 488 nm/RIU and 500 nm/RIU, respectively, were achieved after analyzing both cases.